Projection-Based Correlated Wave Function in Density Functional Theory Embedding for Periodic Systems.

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Accurate electronic structure calculations are crucial for understanding chemical reactions on surfaces.
• Embedding methods are needed to treat complex systems by dividing them into "active" and "environment" subsystems.
• Existing methods may struggle with systems exhibiting periodic boundary conditions.

Purpose of the Study:

• To introduce a novel embedding method for periodic systems combining Density Functional Theory (DFT) and Wave Function (WF) methods.
• To enable accurate calculations for systems where the active subsystem requires high-level treatment (WF) and the environment is described by DFT.
• To provide flexibility in treating the active subsystem as either periodic or a molecular cluster.

Main Methods:

• A level shift projection operator-based embedding method is presented.
• The method supports k-point sampling for periodic systems.
• It allows for "periodic-in-periodic" and "cluster-in-periodic" embedding schemes.

Main Results:

• The method is shown to be equivalent to canonical DFT for the full system in a limiting case.
• Demonstrated the accuracy of "cluster WF-in-periodic DFT" embedding for calculating adsorption energies.
• Successfully computed the absorption energy of CO on a Si(100)-2×1 surface.

Conclusions:

• The developed embedding method offers a powerful and flexible approach for electronic structure calculations of periodic systems.
• This method accurately captures chemical phenomena at surfaces, such as adsorption.
• It opens avenues for more precise theoretical investigations in surface science and catalysis.